Recently, semiconductor devices tend to be highly integrated. As one method of realizing this, a three-dimensional structure in which electrodes or the like are three-dimensionally arranged has been proposed.
In a process of forming a three-dimensional structure of a flash memory, it is necessary to alternately laminate an insulating film and a sacrificial film. However, due to a difference in thermal expansion coefficient between the insulating film and the sacrificial film, stress is applied to a silicon wafer, causing a phenomenon in which the laminated film is broken down in the formation process of the three-dimensional structure. Such a phenomenon may lead to a degradation in characteristics of the semiconductor device.